Combined potentiometer and switching structure

ABSTRACT

A combined potentiometer and switching structure including wiper contacts fixed to a shaft and having contacting engagement with an annular resistor and a pair of switching rings. The wiper contacts are located coincident, or in phase relation. The switching rings are each provided with an interrupted area, such areas are located in an arc complemental to the arc of the resistor and are circumferentially spaced apart a distance not greater than the length of the resistor contacting surface whereby, during rotation of the shafts, circuits connected to the switch rings are opened at different positions with respect to the resistor wiping contact. An annular supporting ring formed of electrical insulation material and provided with a central rib projecting from the inner surface thereof serves as a convenient mounting for the switch rings.

[72] Inventor United States Patent Paul F. Gerwitz West Covina, Calii.[21] Appl. No. 828,618 [22] Filed May 28, 1969 [45] Patented June 22,1971 (73] Assignee Spectral Electronics Corporation City of Industry,Calif.

[54] COMBINED POTENTIOMETER AND SWITCHING STRUCTURE 4Claims,7DrawingFigs.

[52] U.S.Cl. 338/172, 338/146,338/166,338/174,338/l98 [51] Int.C lH01c5/08 [50] FieIdofSearch 338/118,

[561 References Cited UNITED STATES PATENTS 2,859,315 11/1958 .Ioerndt338/137 X 2,926,321 2/1960 Stein 2,929,040 3/1960 Barden 3,007,12610/1961 Fraser Primary Examiner-Lewis H..Myers Assistant Examiner-GeraldP. Tolin AnomeysHarry G. Martin, Jr. and .1. Raymond Curtin ABSTRACT: Acombined potentiometer and switching structure including wiper contactsfixed to a shaft and having contacting engagement with an annularresistor and a pair of switching rings. The wiper contacts are locatedcoincident, or

- in phase relation. The switching rings are each provided with aninterrupted area, such areas are located in an arc complemental to thearc of the resistor and are circumferentially spaced apart a distancenot greater than the length of the resistor contacting surface whereby,during rotation of the shafts, circuits connected to the switch ringsare opened at different positions with respect to the resistor wipingcontact. An annular supporting ring formed of electrical insulationmaterial and provided with a central rib projecting from the innersurface thereof serves as a convenient mounting for the switch rings.

PATENTEU JUN22 IBYI SHEET 10F 2 INVENTOR. PAUL F. GERWITZ.

BY Q

ATTORNEY.

COMBINED POTENTIOMETER AND SWITCHING STRUCTURE BACKGROUND OF THEINVENTION SUMMARY OFfTHE INVENTION This invention has to do withacombined potentiometer and circuit switching structure. Thepotentiometer is of the conventional annular type having a circularcontacting surface engaged by a wiping contact fixed to a shaft. Asecond wiper contact is affixed to the shaft and is phased with theresistor wiper contact. This second contact engages a pair of conductingswitch rings. A circuit is formed from the second wiper contact througheach of the switch rings. The switch rings are formed with interruptedareas whereby, at different positions of the resistor wiper contact, theswitching circuits are opened.

More particularly, the invention is directed to a structural arrangementwhich is economical to manufacture and convenient to assemble to producea device having very small overall dimensions.

BRIEF DESCRIPTION :OF THE DRAWINGS FIG. 1 is a side elevational view ofa structure embodying my invention;

FIG. 2 is an end elevation looking to the right, FIG. 1;

FIG. 3 is an enlarged sectional view taken on a line corresponding toline 3-3, FIG. 2;

FIG. 4 is a sectional view taken on line 4-4, FIG. 3;

FIG. 5 is an exploded view of the switch rings and resistor illustratingthe orientation of such parts; and

FIG. 6 is a schematic diagram illustrating an arrangement of theresistor and switching rings.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus consists of acasing having sections 10, 11. The section 10 is formed with an end wall12, having an inwardly extending cylindrical hub 13. The hub 13 isprovided with a central aperture forming a bearing in which an enlargedportion 14 of an actuating shaft 15 is joumaled.

The casing section 11 is provided with a discoidal closure 16 which isformed with a central aperture arranged in axial alignment with theaperture in the flange 13 and forming a second bearing for the shaft 15.The end member 16 is attached to the section 11 by a clamp ring 17.

A resistor 18 of annular configuration is fixedly mounted in the section11. The inner surface-20 of the resistor is a contact surface over whicha wiper contact 21 is moved. The contact 21 is fixed on one end of anarcuate spring member 22, the opposite end of which is fixed to an arm23 which, in turn, is fixedly secured to a sleeve 25 of insulatingmaterial fixedly secured to the shaft 15. A collector ring 27 isattached in conductive relation to the arm 23 and is connected to aterminal 28 by a brush 30. T

The casing section 10 is formed at its inner end with a cylindricalflange 33 formed with an annular shoulder 34. The casing 11 is formedwith a circular flange 35 snugly engaging the flange 33 and abuttingagainst the shoulder 34. The sections are held together by a clamp ring37 A pair of switching rings 38, 40, are fixedly mounted in the flange33 of the casing section 10. In the arrangement disclosed, the switchingrings are mounted in an annular member 41, fixedly mounted in the flange33 and having a flange 43 extending radially inwardly between the switchrings 38, 40. The

inner contacting surfaces of the switch rings are engaged by a wipercontact 45 fixed on one end of an arcuate leaf spring member 46, theopposite end of which is fixed to an arm 47 which, in turn, is fixed tothe sleeve 25. A collecting ring 50 is fixed in conducting relation tothe arm 47, and is connected to a terminal 53 by a brush 54. Thecollector rings 27, 50, are separated by a ring of insulating material55.

The contacting surface 20 of the resistor 18 extends circumferentiallyless than 360--in the structure shown about 325. The switching rings 38,40, are each formed with an interrupted area in their inner contactingsurfaces. For economy in manufacture, these interrupted areas arepreferably in the form of a notch 58 in ring 38, and a notch 60 in ring40. The switch rings 38, 40 are fixed in the insulating member 41 withthe notches 58, 60 spaced apart circumferentially a distance less thanthe circumferential extent of the effective contacting surface 20 of theresistor 18.

The switch ring 40 is connected to a terminal by wire 71 convenientlyextended through the apertures 63, 64 in the switching rings and member41, see FIG. 3. The switching ring 38 is connected to a terminal 72 bywire 73. One end of the resistor 18 is connected to a terminal 75 bywire 76. Accordingly, a switching circuit is established from terminal53 to terminal 70 through switching -ring 40, and a second switchingcircuit is established through terminal 53 and terminal 72 throughswitch ring 38.

One convenient method of assembling the switch rings with theinterrupted areas in the desired phase relation involves forming therings with through apertures 63. The member 41 is formed with a throughaperture 64 in the flange 43. The apertures 63, 64 are aligned and a pinis extended through the apertures. The rings are pressed into the member41, or otherwise secured therein, and the member 41 is pressed, orotherwise secured, in the section 10. The alignment pin is then removedand the wire 71 is run through the apertures and fixed to the ring 40.The sections'10, 11 are oriented and fixedly clamped together by theband 37. This method of assembly, together with the product providedwith the openings necessary to accomplish the method, are the subject ofa Pat. application Ser. No. 828,617, filed concurrently with thisapplication and assigned to a common assignee.

' Another method of assembling the unit forming the subject of thisinvention would involve arranging the switch rings without apertures inproper position on the ring 41 with the aid of proper alignment indiciaand securing same with adhesive material. An opening might then beformed in the base portion of the ring for a conductor. Such a procedurewould not, of course, be as efficient as providing openings, inalignment, through the parts as described above.

In FIG. 6, the interrupted areas in the rings 38, 40 are indicated at58, 60 and as being located coincident with the ends of the resistor 18.The wiper contacts 21, 45 are fixed in phase relation, see also FIG. 4.Accordingly, when the resistor wiper '21 is positioned at the rightendof the resistor, the contact 45 is in register with the notch 58in theswitching ring 39. When the resistor wiper has been moved to the leftend of the resistor, the contact 45 is in registration with the notch 60in the switching ring 40. At intermediate positions of the wipercontacts, both switching circuits are energized.

It will be apparent the interrupted areas of the switching means may bephased to provide interruption of the switching circuits at variouspreselected positions of the resistor wiper contact 21.

While I have described a preferred embodiment of the invention, it willbe understood the invention is not limited thereto since it may beotherwise embodied within the scope of the following claims.

Iclaim:

1. A combined potentiometer and switching structure comprising a casing,a shaft journaled in said casing, a resistor fixedly mounted in thecasing and having an arcuate contact surface arranged concentrically ofsaid shaft and extending less than 360, a resistor wiper contact fixedto said shaft and movable along said contact surface from one endthereof to the other upon rotation of said shaft, a terminal connectedto one end of said resister and a terminal connected to said wipercontact, an annular ring formed of dielectric material disposed in saidcasing, said ring having a central rib formed thereon, a pair ofconducting switch rings mounted on said annular ring, each of said ringshaving a circular contacting surface arranged in concentric relation tosaid shaft, an arm fixed to said shaft and having a switch wiper contactmeans yielding engaging the contacting surfaces of said rings, saidswitch wiper contact means being located coincident with said resistorwiper contact, the contacting surface of each of said rings being formedwith an interrupted area, said rings being fixedly mounted in saidcasing with said interrupted areas being spaced apart circumferentiallya distance not greater than the circumferential extent of the contactsurface of said resistor, a switching circuit including a wiper terminalconnected to said switching wiper contact, and a terminal connected toone of said rings, a second switching circuit including said wipercontact terminal, and a tenninal connected to the other of said rings,whereby one of said switching circuits is open at one position of saidresistor wiper contact, and said other switching circuit is open atanother position of said resistor wiping contact. v

2. A combined potentiometer and swit'chingstructure as set forth inclaim 1, wherein said interrupted areas in said switch rings consist ofnotches formed in the contacting surfaces of said rings.

3. A combined potentiometer and switching structure as set forth inclaim I, wherein said switch wiper contact means consists of a one-piececontact engaging the contacting surfaces of both of said rings.

4. A combined potentiometer and switching structure as set forth inclaim 1, wherein said interrupted areas of said switch rings are locatedrespectively complemental to the ends of the contact surface of saidresistor.

1. A combined potentiometer and switching structure comprising a casing,a shaft journaled in said casing, a resistor fixedly mounted in thecasing and having an arcuate contact surface arranged concentrically ofsaid shaft and extending less than 360*, a resistor wiper contact fixedto said shaft and movable along said contact surface from one endthereof to the other upon rotation of said shaft, a terminal connectedto one end of said resister and a terminal connected to said wipercontact, an annular ring formed of dielectric material disposed in saidcasing, said ring having a central rib formed thereon, a pair ofconducting switch rings mounted on said annular ring, each of said ringshaving a circular contacting surface arranged in concentric relation tosaid shaft, an arm fixed to said shaft and having a switch wiper contactmeans yielding engaging the contacting surfaces of said rings, saidswitch wiper contact means being located coincident with said resistorwiper contact, the contacting surface of each of said rings being formedwith an interrupted area, said rings being fixedly mounted in saidcasing with said interrupted areas being spaced apart circumferentiallya distance not greater than the circumferential extent of the contactsurface of said resistor, a switching circuit including a wiper terminalconnected to said switching wiper contact, and a terminal connected toone of said rings, a second switching circuit including said wipercontact terminal, and a terminal connected to the other of said rings,whereby one of said switching circuits is open at one position of saidresistor wiper contact, and said other switching circuit is open atanother position of said resistor wiping contact.
 2. A combinedpotentiometer and switching structure as set forth in claim 1, whereinsaid interrupted areas in said switch rings consist of notches formed inthe contacting surfaces of said rings.
 3. A combined potentiometer andswitching structure as set forth in claim 1, wherein said switch wipercontact means consists of a one-piece contact engaging the contactingsurfaces of both of said rings.
 4. A combined potentiometer andswitching structure as set forth in claim 1, wherein said interruptedareas of said switch rings are located respectively complemental to theends of the contact surface of said resistor.